Recently, for the multimedia processing of information employed for a communication system that uses mobile cellular terminals, as typified by mobile phones or the like, the transmission not only of audio data but also of large volumes of data for static pictures, moving pictures, etc., has come to be commonly accepted. In order to provide for the transmission of large volumes of data, methods for employing high frequency wireless bands to obtain high transmission rates have been frequently discussed.
However, in cases wherein high frequency wireless bands are used, while high transmission rates can be expected over short distances, attenuation due to transmission distances is excessive. Therefore, the area covered by each base station is reduced, and many more base stations must be installed. Since considerably high costs are involved in the installation of a base station, a technique whereby an increase in the number of base stations is prevented, and a communication service can be provided, has been strongly demanded.
Conventional art related to this is exemplified, for example, by a technique described in patent document 1. According to the conventional art in patent document 1, in order to improve diverse effects, a reception signal is synthesized that employs both a communication network, established between a base station and a mobile station via a cellular, dedicated wireless channel, and an adhoc network formed between mobile stations. Further, the conventional art discloses a technique whereby, in a case wherein a relay station detects an error in a received signal, the relay station abandons the relay signal and issues a retransmission request to a base station, and whereby, in a case wherein an error is not found in a signal that is received again, the relay station relays the signal to the mobile station. And a technique is disclosed whereby, even in a case wherein the relay station detects an error in a received signal, the relay terminal relays the signal to a mobile station, unconditionally.    Patent Document 1: JP-A-2001-189971